﻿﻿using System;
using System.Drawing;
using System.Drawing.Imaging;
using System.Web.UI;
using System.Drawing.Drawing2D;
using System.IO;
using System.Web;

namespace Repid.Utility.Helper
{
    /// <summary>
    /// 生成验证码
    /// </summary>
    public static class ValidateHelper
    {
        public static string VerifyCode()
        {
            ValidateCode vc = new ValidateCode();

            string code = vc.CreateVerifyCode();

            vc.CreateImageOnPage(code);

            return code;
        }

        /// <summary>
        /// 验证码
        /// </summary>
        public class ValidateCode
        {
            #region 验证码长度

            int length = 4;

            /// <summary>
            /// 验证码长度
            /// </summary>
            public int Length
            {
                get { return length; }
                set { length = value; }
            }

            #endregion

            #region 是否使用扭曲效果

            bool isTwist = false;

            /// <summary>
            /// 是否使用扭曲效果 true使用 false不使用
            /// </summary>
            public bool IsTwist
            {
                get { return isTwist; }
                set { isTwist = value; }
            }

            #endregion

            #region 验证码字体大小

            int fontSize = 12;

            public int FontSize
            {
                get { return fontSize; }
                set { fontSize = value; }
            }

            #endregion

            #region 边框补

            int padding = 1;

            public int Padding
            {
                get { return padding; }
                set { padding = value; }
            }

            #endregion

            #region 是否输出燥点

            bool chaos = true;
            /// <summary>
            /// 是否输出燥点
            /// </summary>
            /// 
            public bool Chaos
            {
                get { return chaos; }
                set { chaos = value; }
            }

            #endregion

            #region 输出燥点的颜色

            Color chaosColor = Color.LightGray;

            /// <summary>
            /// 输出燥点的颜色
            /// </summary>
            /// 
            public Color ChaosColor
            {
                get { return chaosColor; }
                set { chaosColor = value; }
            }

            #endregion

            #region 自定义背景色

            Color backgroundColor = Color.White;

            public Color BackgroundColor
            {
                get { return backgroundColor; }
                set { backgroundColor = value; }
            }

            #endregion

            #region 自定义随机颜色数组

            Color[] colors = { Color.Black, Color.Red, Color.DarkBlue, Color.Fuchsia, Color.Green, Color.Orange, Color.Brown, Color.DarkCyan, Color.Purple };

            public Color[] Colors
            {
                get { return colors; }
                set { colors = value; }
            }

            #endregion

            #region 自定义字体数组

            string[] fonts = { "Arial", "Georgia" };

            public string[] Fonts
            {
                get { return fonts; }
                set { fonts = value; }
            }

            #endregion

            #region 字符类型

            string codetype = "3";

            /// <summary>
            /// 要验证码的形式，1=纯数字 2=纯字母 3=大全
            /// </summary>
            public string CodeType
            {
                set { codetype = value; }
                get { return codetype; }
            }

            #endregion

            #region 自定义随机码字符串序列(使用逗号分隔)

            string codeSerial = "0,1,2,3,4,5,6,7,8,9,a,b,c,d,e,f,g,h,i,j,k,l,m,n,o,p,q,r,s,t,u,v,w,x,y,z,A,B,C,D,E,F,G,H,I,J,K,L,M,N,O,P,Q,R,S,T,U,V,W,X,Y,Z";

            /// <summary>
            /// 自定义随机码字符串序列(使用逗号分隔)
            /// </summary>
            public string CodeSerial
            {
                get
                {
                    switch (codetype)
                    {
                        case "1":
                            codeSerial = "0,1,2,3,4,5,6,7,8,9";
                            break;
                        case "2":
                            codeSerial = "a,b,c,d,e,f,g,h,i,j,k,m,n,o,p,q,r,s,t,u,v,w,x,y,z,A,B,C,D,E,F,G,H,J,K,L,M,N,O,P,Q,R,S,T,U,V,W,X,Y,Z";
                            break;
                        case "3":
                            codeSerial = "1,2,3,4,5,6,7,8,9,a,b,c,d,e,f,g,h,i,j,k,m,n,p,q,r,s,t,u,v,w,x,y,z,A,B,C,D,E,F,G,H,J,K,L,M,N,P,Q,R,S,T,U,V,W,X,Y,Z";
                            break;
                        default:
                            codeSerial = "0,1,2,3,4,5,6,7,8,9";
                            break;
                    }
                    return codeSerial;
                }
            }

            #endregion

            #region 产生波形滤镜效果

            private const double PI = 3.1415926535897932384626433832795;
            private const double PI2 = 6.283185307179586476925286766559;

            /// <summary>
            /// 正弦曲线Wave扭曲图片
            /// </summary>
            /// <param name="srcBmp">图片路径</param>
            /// <param name="bXDir">如果扭曲则选择为True</param>
            /// <param name="nMultValue">波形的幅度倍数，越大扭曲的程度越高，一般为3</param>
            /// <param name="dPhase">波形的起始相位，取值区间[0-2*PI)</param>
            /// <returns></returns>
            public System.Drawing.Bitmap TwistImage(Bitmap srcBmp, bool bXDir, double dMultValue, double dPhase)
            {
                System.Drawing.Bitmap destBmp = new Bitmap(srcBmp.Width, srcBmp.Height);

                // 将位图背景填充为白色
                System.Drawing.Graphics graph = System.Drawing.Graphics.FromImage(destBmp);
                graph.FillRectangle(new SolidBrush(System.Drawing.Color.White), 0, 0, destBmp.Width, destBmp.Height);
                graph.Dispose();

                double dBaseAxisLen = bXDir ? (double)destBmp.Height : (double)destBmp.Width;

                for (int i = 0; i < destBmp.Width; i++)
                {
                    for (int j = 0; j < destBmp.Height; j++)
                    {
                        double dx = 0;
                        dx = bXDir ? (PI2 * (double)j) / dBaseAxisLen : (PI2 * (double)i) / dBaseAxisLen;
                        dx += dPhase;
                        double dy = Math.Sin(dx);

                        // 取得当前点的颜色
                        int nOldX = 0, nOldY = 0;
                        nOldX = bXDir ? i + (int)(dy * dMultValue) : i;
                        nOldY = bXDir ? j : j + (int)(dy * dMultValue);

                        System.Drawing.Color color = srcBmp.GetPixel(i, j);
                        if (nOldX >= 0 && nOldX < destBmp.Width
                         && nOldY >= 0 && nOldY < destBmp.Height)
                        {
                            destBmp.SetPixel(nOldX, nOldY, color);
                        }
                    }
                }

                return destBmp;
            }

            #endregion

            #region 生成校验码图片

            /// <summary>
            /// 生成字符验证码图片
            /// </summary>
            /// <param name="code">字符</param>
            /// <returns></returns>
            public Bitmap CreateImageCode(string code)
            {
                int fSize = FontSize;
                int fWidth = fSize + Padding;

                int imageWidth = (int)(code.Length * fWidth) + 4 + Padding * 2;
                int imageHeight = fSize * 2 + Padding;

                System.Drawing.Bitmap image = new System.Drawing.Bitmap(imageWidth, imageHeight);

                Graphics g = Graphics.FromImage(image);

                g.Clear(BackgroundColor);

                Random rand = new Random();

                int left = 0, top = 0, top1 = 1, top2 = 1;

                int n1 = (imageHeight - FontSize - Padding * 2);
                int n2 = n1 / 4;
                top1 = n2;
                top2 = n2 * 2;

                Font f;
                Brush b;

                int cindex, findex;

                //随机字体和颜色的验证码字符
                for (int i = 0; i < code.Length; i++)
                {
                    cindex = rand.Next(Colors.Length - 1);
                    findex = rand.Next(Fonts.Length - 1);

                    f = new System.Drawing.Font(Fonts[findex], fSize, System.Drawing.FontStyle.Bold);
                    b = new System.Drawing.SolidBrush(Colors[cindex]);

                    if (i % 2 == 1)
                    {
                        top = top2;
                    }
                    else
                    {
                        top = top1;
                    }

                    left = i * fWidth;

                    g.DrawString(code.Substring(i, 1), f, b, left, top);
                }

                //干扰线
                for (int i = 0; i < 5; i++)
                {
                    int x1 = rand.Next(image.Width);
                    int x2 = rand.Next(image.Width);
                    int y1 = rand.Next(image.Height);
                    int y2 = rand.Next(image.Height);

                    g.DrawLine(new Pen(ChaosColor), x1, y1, x2, y2);
                }

                //给背景添加随机生成的燥点
                if (this.Chaos)
                {
                    Pen pen = new Pen(ChaosColor, 0);
                    int c = Length * 50;

                    for (int i = 0; i < c; i++)
                    {
                        int x = rand.Next(image.Width);
                        int y = rand.Next(image.Height);

                        g.DrawRectangle(pen, x, y, 0.5f, 0.5f);
                    }
                }

                //画一个边框 边框颜色为Color.Gainsboro
                g.DrawRectangle(new Pen(Color.Gainsboro, 0), 0, 0, image.Width - 1, image.Height - 1);
                g.Dispose();


                //产生波形
                if (isTwist) image = TwistImage(image, true, 8, 4);

                return image;
            }

            /// <summary>
            /// 禁用缓存
            /// </summary>
            /// <param name="context">httpcontext</param>
            private static void DisableHttpCache(System.Web.HttpContext context)
            {
                ////清除http缓存
                context.Response.ClearHeaders();
                context.Response.ClearContent();
                ////禁用http缓存
                //// http 1.1
                context.Response.AddHeader("Expires", "Mon, 26 Jul 1997 05:00:00 GMT");
                context.Response.AddHeader("Cache-Control", "no-store, no-cache, max-age=0, must-revalidate");
                //// http 1.0
                context.Response.AddHeader("Pragma", "no-cache");
            }

            #endregion

            #region 将创建好的图片输出到页面

            /// <summary>
            /// 将创建好的图片输出到页面
            /// </summary>
            /// <param name="code">验证码字符串</param>
            /// <param name="context"></param>
            public void CreateImageOnPage(string code)
            {
                System.IO.MemoryStream ms = new System.IO.MemoryStream();
                Bitmap image = this.CreateImageCode(code);

                image.Save(ms, System.Drawing.Imaging.ImageFormat.Png);

                HttpContext context = HttpContext.Current;
                context.Response.ClearContent();
                context.Response.ContentType = "image/png";
                context.Response.BinaryWrite(ms.GetBuffer());

                ms.Close(); ms = null; image.Dispose(); image = null;
            }

            #endregion

            #region 生成随机字符码

            public string CreateVerifyCode(int codeLen)
            {
                if (codeLen == 0)
                {
                    codeLen = Length;
                }

                string[] arr = CodeSerial.Split(',');

                string code = "";

                int randValue = -1;

                Random rand = new Random(unchecked((int)DateTime.Now.Ticks));

                for (int i = 0; i < codeLen; i++)
                {
                    randValue = rand.Next(0, arr.Length - 1);

                    code += arr[randValue];
                }

                return code;
            }

            public string CreateVerifyCode()
            {
                return CreateVerifyCode(0);
            }

            #endregion
        }
    }
}
